Beginning in 1989, EPA required gasoline to meet volatility standards to decrease evaporative emissions of gasoline fuels in the automover parts summer months when ozone levels are typically at their highest. In the early 1990s, EPA began monitoring the winter oxygenated automobile fuels program implemented by the states to help control fuel emissions of carbon monoxide during the winter months, and established the reformulated gasoline (RFG) program to reduce fuel emissions of smog-forming and toxic pollutants.
More recently, EPA promulgated new regulations automobile parts setting standards for gasoline fuels toxics performance levels and standards for low sulfur gasoline fuels to reduce harmful air pollution and help ensure the automobile effectiveness of advanced emission control technologies in automobile vehicles.